Unless it’s a rockumentary like Sound City or 20 Feet From Stardom, the soundtrack to a documentary usually isn’t much more than an afterthought. But for Jodorowsky’s Dune, the new documentary about one of the greatest films never made, the music is an essential part in bringing to life a film that doesn’t exist. San Francisco composer Kurt Stenzel has done exactly that with his synth-laden, spooktacular mood setting composition for the film.

The performance artist/musician had never been asked to make a soundtrack before, but his work in the electro-art group Spacekraft caught the attention of the filmmakers. His synthesizer list is extensive, ranging from Radioshack toys to Moog to custom Dave Smith creations. The result is pulsing, warped and sometimes eerie sounds that create a sense of uncertainty. It would have had a big impact on Jodorowsky’s film vision for the epic science fiction novel, had it ever been made.

Stenzel’s ambient music is non-offensive and, like abstract art, can be interpreted in many ways—unlike his former project, the New York punk band Six and Violence. The self-taught musician admits he doesn’t have “chops” in the traditional sense, meaning he won’t bust out with a Chopin etude on request. But he does know his way around a synthesizer, and his music these days is about texture and timbre more than virtuosity.

Stenzel’s texture on Jodorowsky’s Dune is reminiscent of Isao Tomita, the pioneering Japanese musician who rose to popularity with his futuristic synthesizer renditions of Holst’s Planets suite and pieces of the Star Wars soundtrack in the 1970s. Stenzel grew up in a “classical music household,” and is familiar with Tomita’s work. He’s also a big fan of the Krautrock genre, especially Rodelius and his group, Cluster. When Dune director Frank Pavich was looking for a “Tangerine Dream type soundtrack,” Stenzel was the obvious choice.

Spacekraft’s music is also represented in the film. About nine minutes of the group’s music was left in the film after Stenzel sent over some music “as a placeholder” to Pavich, while he worked on more original music. “Some things just kind of stuck,” says Stenzel. The group is largely performance art these days, with a whole crew of “flight attendants” and more accompanying the experience of a Spacekraft show, which can be seen usually at art galleries and grand openings. Listeners can sit in airline chairs and control the music with their own iPhones, or take personality tests during the performance. “The whole thing is designed to take you somewhere else,” says Stenzel. “We’re kind of weird and make some drug references here and there,” he cautions. Sometimes, the public doesn’t quite understand what’s going on. “People ask if we’re a software company, or Scientologists, or whatever.” For the record, they’re neither.

“We’re somewhere between the pretentious art world and the happy-go-lucky-Bay-Area-friendly-lets-just-do-this-for-fun kind of thing,” says Stenzel.

The soundtrack will be released soon in full analog glory on a double-LP. Stenzel says he’s now interested in writing more music for film. “I like to be challenged,” he says. “This one, I was already doing this type of music… I would love to do a drama or something different.”